Spirit Airlines is an ultra-low cost carrier that serves passengers in the United States, the Caribbean, and Latin America.

The airline had already been in hot water earlier this week for escorting a woman and three men off a plane for questioning on Tuesday. They were aboard a flight due to leave Baltimore for Chicago O’Hare International Airport.

This interruption in the flight’s departure came after a witness reported alleged “suspicious activity” to the flight crew, according to Maryland Transportation Authority police.

Police said the “suspicious activity” was one of the passengers watching a news report on a smartphone. Other passengers told the Baltimore Sun the four passengers were of Middle Eastern descent, but police would not release any information about them.

The Council on American-Islamic Relations said the passengers were targets of racial profiling and has sought an apology from the airline.